The HTC One M9 Android 6.0 Marshmallow update is still on track to arrive before the end of the year, but some new details have emerged suggesting the company could be moving along quicker than many expected. The update has leaked in a slew of images, suggesting the update many be here sooner than we all thought.

In late September Google officially unveiled Android 6.0 Marshmallow, the update to Android 5.1 Lollipop. It was released on October 5th, and HTC promised to deliver an update to the latest new and improved software before the end of the year.

Earlier this month at least one version of the older HTC One M8 received Android 6.0 Marshmallow, but the new HTC One M9 and carrier versions still have at least a month to go, if not longer. Below are multiple screenshots showing the HTC One M9 Android 6.0 Marshmallow update, progress, and the new HTC Sense UI 7.0 as well.

In a post to Twitter HTC’s Jason Mackenzie mentioned the sweet update to Android 6.0 Marshmallow is coming to multiple HTC devices soon, and their last two flagship smartphones will receive update before then end of the year. Essentially promising a 90 day window in which the updates will arrive.

Serving up Marshmallow sweetness real soon. Android 6.0 to start hitting HTC before the end of the year: pic.twitter.com/axITsYSyn9

As owners can see above, the tweet confirms that the somewhat popular HTC One M8 and newer HTC One M9 will see Android 6.0 Marshmallow updates before the end of 2015. The words are “beginning end of 2015” which means the updates will begin rolling out before the end of the year, but might not reach all users by then.

Typically HTC updates the devices outside of the United States, or international and unlocked developer models first, then move to the US. Carriers like AT&T, Verizon and T-Mobile have a strict update testing phase that often causes 4-6 weeks of delays, if not longer. So even if the update is ready today, it still would need to be tested and cleared before being released in the United States on any and all carriers.

That being said, it looks like that’s exactly what’s happening, and the HTC One M9 update to Marshmallow is right on track. Android 6.0 brings a host of new features, improved performance and battery life, Android Pay, Doze to better battery life and more.

Late last night and this morning the popular HTC developer and leakster @LlabTooFer posted a slew of photos on Twitter showing off the update progress, Android 6.0 on the HTC One M9, and a few screenshots of HTC Sense UI 7.0 as well.

The company covers stock Android with their own interface and skin, called HTC Sense, similar to Samsung’s Touchwiz that makes Android look nothing like Google’s stock release on Nexus smartphones and tablets.

HTC Sense delivers new features, visual changes, HTC Blinkfeed news, HTC Zoe camera features, and a lot more. And while we don’t know what else will be added with HTC Sense UI 7.0 when it arrives next year with this update and on the HTC One M10, we’re getting a small preview of it here today.

This leakster was able to share multiple images and screenshots of Android 6.0 for the HTC One M9, but there was no mention of performance, new features, or any potential release date.

If prior years are any indication, we could see the HTC One M9 (and M8) Android 6.0 Marshmallow update start rolling out sometime in December, if not sooner, then the update will arrive for devices in the United States. HTC always starts outside the US first, fixes any small bugs or problems, then begins a wider rollout here with carriers.

It’s worth noting that last month HTC released a new phone called the HTC One A9, which already has the latest Android 6.0 Marshmallow release, and promised they’ll deliver Android updates within 15 days of when Google releases it for Nexus phones and tablets. That’s a big claim, and hopefully the same quick updates start emerging for regular phones like the HTC One M8 and One M9.

We still don’t have any estimated release date, but going off of HTC’s earlier comments, expect a late December or early January release date. Although these images seem to suggest the update is closer to being released than we all thought. Stay tuned for more details, and hopefully Android 6.0 is here sooner rather than later.